# CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

## Project Overview

**Aventures En Egipte (AEE)** — a retro-style 2D game written in C++ using SDL3. The game uses a software-rendered 8-bit paletted graphics engine (320x200, 256 colors) with an OpenGL CRT shader pass, custom audio (JailAudio replacing SDL_Mixer), and GIF-based assets. The codebase and commit messages are in Valencian/Catalan.

## Build

```bash
# Linux
cmake -B build
cmake --build build

# Windows (MinGW)
cmake -B build -G "MinGW Makefiles"
cmake --build build
```

Dependencies: SDL3, OpenGL. Uses CMake (minimum 3.10) with C++20.

The executable is output to the project root. The `data/` folder contains runtime assets (GIF images, OGG music, GLSL shader) and must be in the working directory at runtime.

## Architecture

### Custom "Jail" Engine Libraries (prefix: J)

All engine modules are flat C-style APIs (no classes), prefixed by subsystem:

- **JG** (`source/core/jgame`) — Game loop timing: init/finalize, fixed-timestep update via `JG_ShouldUpdate()`
- **JD8** (`source/core/jdraw8`) — 8-bit paletted software renderer. 320x200 screen buffer (`JD8_Surface` = `Uint8*`), palette-indexed blitting with color-key transparency, fade effects. `JD8_Flip()` converts the indexed buffer to ARGB, uploads to SDL texture, and renders through the CRT shader
- **JA** (`source/core/jail_audio`) — Custom audio mixing using SDL3 audio streams directly (OGG via stb_vorbis, WAV). Manages music and sound channels independently
- **JI** (`source/core/jinput`) — Input: keyboard state polling, key debouncing, cheat code detection
- **JF** (`source/core/jfile`) — File I/O: supports loading from filesystem folder or a packed resource file (`.jrf`). Currently uses folder mode (`data/`)
- **shader** (`source/core/jshader`) — OpenGL post-processing shader (CRT effect) applied to the back buffer

### Configuration System (`source/game/`)

Follows the pattern from `jaildoctors_dilemma`:

- **defines.hpp** �� Game-wide constants (window title, version, screen dimensions)
- **defaults.hpp** — Default values for all persistent options (audio, game)
- **options.hpp/cpp** — `Options` namespace with structs, inline globals, and YAML load/save API. Config persists to `~/.config/jailgames/aee/config.yaml` (Linux), `%APPDATA%/jailgames/aee/` (Windows)

### Game Modules (`source/game/`)

- **ModuleSequence** — Non-gameplay screens: intro, menu, slides, banners, credits, death screen. State machine entry point (state=1)
- **ModuleGame** — Core gameplay loop. Owns and orchestrates all game objects. State=0
- **Sprite** — Base class for animated entities (frame/animation data via `Entitat`)
- **Prota** — Player character ("Sam"), extends Sprite
- **Mapa** — Level map with tomb grid (16 tombs), items (treasure, keys, pharaoh, mummy, scroll, diamond), door logic
- **Momia** — Enemy: mummies
- **Bola** — Enemy: projectile ball
- **Marcador** — HUD/scoreboard
- **info** — Global game state namespace (room number, pyramid, money, diamonds, lives, etc.)

### External Libraries (`source/external/`)

- `gif.h` — Header-only GIF decoder
- `stb_vorbis.h` — stb single-header OGG decoder
- `fkyaml_node.hpp` — Header-only YAML parser (fkYAML v0.4.2)

### Main Loop (`source/main.cpp`)

A state machine alternates between `ModuleSequence` (state 1) and `ModuleGame` (state 0). Each module's `Go()` returns the next state (-1 to quit). Modules are allocated/freed each transition.

### Golden Rule: Do Not Touch Gameplay

The original game logic (gameplay, entities, map, scoring, collisions, animations) must remain untouched. All modernization work targets the presentation layer and infrastructure only: window management, configuration/persistence, rendering pipeline (overlay/UI), and build system. Any new feature (save states, options menu, etc.) must be implemented as an overlay on top of the existing game, never by modifying the original gameplay code.

### Key Conventions

- All surfaces are 320x200 = 64000 bytes. Pixel coordinates assume this fixed resolution
- Graphics loaded from GIF files, palettes extracted from GIF headers
- Music files are numbered OGG files (`00000001.ogg` etc.)
- `trick.ini` presence enables the secret character
- Includes use absolute paths from `source/` (e.g., `#include "core/jgame.hpp"`, `#include "game/info.hpp"`)
- Headers use `.hpp` extension; external third-party headers in `source/external/` keep `.h`